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Date:      Tue, 23 Nov 2010 23:21:39 +0800
From:      Adrian Chadd <adrian@freebsd.org>
To:        Larry Vaden <vaden@texoma.net>
Cc:        freebsd-mips@freebsd.org
Subject:   Re: does anyone have a recommendation for a solid FreeBSD-based 802.11b/g/n AP package for MIPS-based APs and CPEs?
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On 23 November 2010 23:01, Larry Vaden <vaden@texoma.net> wrote:

> You have been a very productive fellow while taking exams!

Hah! :) I explicitly didn't do any of this during exams!

> What can you tell us about how the stuck beacon problem is handled
> (and indeed if the problem remains in the development code branch)?

"stuck beacon" is a symptom of many, many potentially inter-related causes.

I've fixed some of the code related problems that upset the AR9160's I
was using.

I can't fix RF issues, nor can I fix issues that require detailed
documentation about the behaviour of the radio. I have almost no
documentation about the atheros stuff and certainly nothing at all
about the radio. All I really have is ath5k/ath9k and some helpful
contacts that answer the (frequent!) questions I have.

I haven't yet sat down and tried to use the AR9280 I have here in any
real way; I'm specifically ignoring it until I've finished off the 11n
TX path. I have to go over the ath9k code to see what bits we're
missing that could impact stability - there's definitely calibration
and TX power related code that we don't have in our HAL. Rui had
problems with the AR9280 stability and I'm thus focusing on the
chipset that -is- closer to working in a useful way (AR9160), even if
it's "old" and "unsupported" today.

> Will Rogers said "Everybody is ignorant, only on different subjects."
> and I'm ignorant about TX.

Well, in summary - the TX descriptor format has changed between
chipsets (ie, what fields mean in the TX descriptors.) The 11n
chipsets have different expectations for programming TX rates, rts/cts
stuff, etc. There's also extra stuff to care about for handling 11n TX
A-MPDU which I'm just going to ignore for the first pass. I've been
slowly figuring out what's going on by reading ath9k/ath5k source and
asking a few atheros people some questions but it's taking (a lot of)
time.

That said, the relevant ath5k/ath9k people have been very, very helpful. :-)

I'm short on free time at the moment and I do need a bit of a break
from concentration, so there's no real timeline for:

* merging my platform work back into -head;
* finishing the AR724x so (in theory) the Bullet M2/M5 can boot FreeBSD;
* finishing up the if_ath TX path code so it works for both legacy and
11n chipsets "right enough" to trust it;
* even thinking about merging any of this initial 11n stuff from
Rui/Sam into -HEAD.

I'll post an update on -mips when I've hacked together the AR724x
support to test.


Adrian



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